We investigated three conjugated polymers, PSBDB-T, P1SBDB-TS, and PSBDB-TS, having different numbers of alkylthio groups. The polymers showed a wide bandgap of 1.76–1.81 eV with broad absorption range from 300–700 nm and were used as donor polymers in organic photovoltaic (OPV) devices with the non-fullerene acceptor, IT-M. By increasing the number of alkythio groups in their chemical structures, the HOMO levels of the polymers down-shifted as −5.46 eV, −5.51 eV and −5.56 eV, and consequently, the V_OC of the OPV cells gradually increased as 0.91 V, 0.92 V and 0.94 V for PSBDB-T, P1SBDB-TS, and PSBDB-TS, respectively. P1SBDB-TS having three alkylthio groups (two for benzo[1,2-b:4,5-b']dithiophene and one for benzo[1,2-c:4,5-c’]dithiophene-4,8-dione unit) showed the best power conversion efficiency of 6.88% among three polymers due to its high crystallinity and low bimolecular recombination in bulk heterojunction system.

我们研究了三种共轭聚合物PSBDB-T，P1SBDB-TS和PSBDB-TS，它们具有不同数量的烷硫基。该聚合物显示出1.76–1.81 eV的宽带隙，吸收范围在300–700 nm之间，并用作带有非富勒烯受体IT-M的有机光伏（OPV）装置的给体聚合物。通过增加其化学结构中烷硫基的数量，聚合物的HOMO能级下移为-5.46 eV，-5.51 eV和-5.56 eV，因此，OPV细胞的V _OC逐渐增加至0.91 V， PSBDB-T，P1SBDB-TS和PSBDB-TS分别为0.92 V和0.94V。具有三个烷硫基的P1SBDB-TS（两个用于苯并[1,2- b：4,5- b ']二噻吩，一个用于苯并[1,2- c：4,5- c '] dithiophene-4,8-​​dione unit）由于其高结晶度和在本体异质结体系中的低双分子重组，在三种聚合物中显示出最佳的功率转换效率，为6.88％。